Automatic toaster and method of controlling the same



-mmh 7, 1939. .w.L .,1 ODGE 2,149,972

AUTOMATIC TOASTER AND METHODF CONTROLLING THE-SAME Filed Deo. 8, 1957 2 Sheets-Sheet 1 O v Q8. Y |29 Inve nim-'1 1 ttr'nzg.

March 7, 1939 W. l.. LODGE 2,149,972

AUTOMATIC ToAsTEE AND METHOD E CONTROLLING TEE SAME Filed Deo. 8, 1937 2 Sheets-Sheet 2 F4 s Z' r4' "Q ,W7 levs ,as /39 T55 nos :97

Is |06 |31 3 23 33 |37 3a '7 4S FY. f8

3 Inventor.- William L. Lodge Nt torneg.

Patented Mar. 7, 1939 UNITED vsTATE's AUTOMATIC TOASTER AND METHOD F CONTROLLING THE SAME William L. Lodge, University,

to McGraw Electric Company,

City, Mo., assigner Chicago, Ill., a

corporation of Delaware Application December 8, 1937, Serial No. 178,723

. 20 Claims.

My invention relates to toasters and particularly to toasting-operation control means for automatic electric toasters.

An object of my invention is to provide a relatively simple means of and method for determining the duration of an operating period of a toaster.

Another object of my invention is to provide a relatively simple timing means for a toaster that lo shall be operable in accordance with the degree of surface hardness of a toasting surface of a slice of bread being toasted;

Another object of my invention is to provide a relatively simple timing means for a toaster, that l5 shall be independent of temperature variations of the toaster and that -shall respond to a predetermined physical condition of a slice of bread being toasted. Other objects of my invention will either be apparent from a description of a device embodying my invention or will be pointed out in the course of such description and will be set forth in the appended claims.

I ha've found thatthe surface hardness of a toasting surface of a slice of bread being toasted is a measure of the degree of toasting which has been effected by heat from the heating means adjacent to the toasting surface. It is well known that the surface of an untoasted slice of bread has little or no hardness, but that on the contrary the surface of a toasted slice of bread is relatively hard and I have found that the increase of hardness is in substantially direct proportion to the degree of toasting. My invention relates in particular to novel means for repeatedly testing the surface hardness of successively diiferent areas of a toasting surface of a slice of bread and for terminating the toasting operation when the hardness of the surface has reached a certain degree.

In the drawings,

Fig. 1 is a View in vertical longitudinal section through a toaster embodying my invention, taken on the line I-I of Fig. 2, shown on a slightly reduced scale, 5 Fig. 2 is a view in vertical lateral section therethrough, taken on the line 2-2 of Fig. 1, also shown on a slightly reduced scale,

Fig. 3 is a fragmentary horizontal sectional view taken on the linel 3-3 of Fig. 5, Y

Fig. 4 is a fragmentary exploded view, in perspective, of certain parts of the device.

Fig. 5 is a fragmentary view in vertical section taken on the line 5-5 of Fig. 8 showing parts of the toaster in non-toasting position,

Fig. 6 is a fragmentary view, similar to that (Cl. 21S-19) of Fig. 5, but showing the parts of the toaster in toasting position,

Fig. '7 is a fragmentary tudinal section, taken on the line 1-1 of Fig.

and,

Fig. 8 is a fragmentary view in horizontal section taken on the line 8--8 of Fig. 5.

I have elected to show my improved control means as applied to a single slice toaster designated by the numeral I I, although I desire it to be understood that my invention is not limited to a single slice toaster nor is it limited to the particular details and elements shown in the drawings and described in the following specification.

The toaster II includes a metal base plate I3 which may be substantially rectangular in shape and of dished form as shown in Figs. 1 and 2 of the drawings.

An outer casing I5 includes front, rear, and side walls, the general shape of the casing being rectangular and having a top or cover I1 associated therewith.. A carrying knob I9 may be secured' to the rear wall of casing I5 to permit of carrying the toaster whenever desired. I

A pair 'of vertically-extending heating elements includes, for each of the respective elements, sheets 2| of electric-insulating material, such as mica, on which is wound a suitable resistor element 23 and while I have shown the resistor 23 as being wound on one face only, I do not desire to. be limited thereto. A pair of vertically-extending side baiile plates 25 are provided, as well as a front intermediate wall 21 and a rear intermediate wall 29. The heating elements cooperate with the front and the rear intermediate Walls to definea toasting chamber, at least so far as its horizontal extent is concerned, while the top surface of the base I3 and the central portion of cover I1 cooperate to further define the toasting chamber. The upper edges of the heating 'elements are held in a well known manner by depending side flanges 'of top frame plates 3l and by top portions of guard wires 33 depending from the top frame plates all in a manner well known inthe art. If desired an opening 34 may be provided in the base plate extending centrally and longitudinally thereof and between the two spaced heating units to permit of the passage of a current of air through the toaster. The cover and the top frame plate are provided with registering openings 34a and 34h to permit of the insertion and removal of slices of bread from the toasting chamber. Y

The front intermediate wall 21 cooperates with the front wall of the casing I5 and the forward 55 view in vertical longiportion of the cov'er I1 to constitute a mechanism chamber 35.

A vertically-extending standard 31 in the shape of a round rod has its lower end held by the base plate |3 while the upper end is held in proper operative position by the front end of the top frame plate 3|. A slider 39 is vertically movable on standard 31 as is also a carriage 4|. The carriage 4| is provided with a portion 43 extending through a vertical slot in the front wall of casing I3 and an actuating knob is secured thereto.

The circuit of the heating elements is controlled by a fixed contact member 41 and a movable contact carried by arm 49 which is pivoted4 on bracket 5I. Contact member 41 and bracket 5| are insulated from and mounted on front intermediate wall 21.

Contact arm 49 is actuated by slider 39 through a linkage comprising a lever 53, of T-shape, and a link 3|. 'I'he rear 'end of lever 53 is pivoted at on the rear intermediate wall 29. The forward end oi' lever 53 carries a cross pin 51, which cro pin extends laterally of the lever and moves in a slot in the lower end of slider 39. Arm 59 of the T-shaped lever is pivoted to the rear end of link 9|. the front end of which is slotted to receive a pin on the upper end of arm 49. A spring 61 which normally holds the pin in the right hand end of the slot permits a slight movement to insure good seating of the contacts. The lower arm 69 of the T-shaped lever extends through the base plate |3 and is drawn to theA right by a coil spring 1|, thus providing the tension which tends to lift slider 39 upwardly, and to disengage contacts 41 and 49. y,

A bread slice support 13 is vertically movable in the space between the two heating elements,

its upper position being shown particularly in Fig. 5 of lthe drawings, this position being referred` to hereinafter as the non-toasting position. The lowermost position is that shown in Fig. 6 of the drawings and will be hereinafter referred to as the toasting position. The bread slice support 13 is secured to slider 39 as by a connecting bar 15 shown particularly inFigs. 6 and 7 of the drawings. It is thus obvious that the bread slice support is moved from its initial or normal non-toasting position to its lower operative toasting positionl by downward movement of the knob 45.

Slider 39 .is provided with a substantially horizontally extending latching lug 11 (see Fig. 2) which lug is adapted to move past and then below the lower end of a latch. arm 19 which latch arm is pivotally mounted on a timing means 3| located in the mechanism chamber 35. It is thus evident that when an'operator depresses knob 45,

' may be of the kind shown in Forbes Patent No.

1,665,735 and actuated means to effect termination of a toasting operation under emergency conditions. Carriage 4| is provided with a lateral extension 93 thereon, the lowefx edge of which is of inverted V-shape as shown more particularly. in Fig. '7 of the drawings and a pin 95 on a rack bar 91 permits of winding up the timer 3| when knob 45 is depressed by an operator. Further details of a structure of this kind are shown in Ireland Patent No. 2,001,362.

As soon as knob 45 is released by the operator the timer spring will start to unwind and cause upward movement of rack bar 91 and of carriage 4 I and it is to be noted that latch arm 19 is provided with a pin 99 at its upper end which may be engaged by. an upper cam surface of portion 33 to cause releasing movement of the latch arm lo and of its lower end portion to therebymove the detent out of engagement with latching lug 11. As stated hereinbefore this is an emergency release so that should the control apparatus which is hereinafter described. fail for any reason to 15 operate properly: termination of a toasting operation would still be effected.

A bracket plate 95 is mounted to slide on standard 31 and has interiitting engagement with a recess 96 in the lower end part of carriage 4'| so 20 that bracket 95 will move vertically upwardly and downwardly vwith carriage 4|. The inner end of bracket 95 has insulatediy mounted thereon a resilient contact arm 91 and a. second non-resilient arm 99 which latter is insulated from bracket 25 95 and from arm 91. A pair of rivets may be utilized to secure the two arms 91 and 99 on bracket 95. A spring |0| extending around standard 31 has one end interfitting with carriage 4| and the other end engaging bracket 95 so that 30 the bracket 95 and the arms 91 and 99 tend to move in a clockwise direction as shown in Fig. 8 of the drawings. The outer surface of arm 99 is rounded as shown particularly in Figs. 2 and 4 of the drawings and is pressed by spring |0| into 35 engagement with the serrated edge |03 of a slot |05 in the front wall 21 through which the arms 91 and 99 extend to the toasting chamber and at one side of a slice of bread |05 resting upon the bread slice support 13. 40

The inner end of armv 91 is provided with a substantially vertically-extending tactile member 01 having its lower end portion secured to arm 91. adjacent its inner end andv having a lower hooked portion extending. around arm 99 to limit 45 the separating movement thereof. 'I'he upper end of member |01 is of substantially the shape shown in Fig. 4, that is of generally bowed-out shape having the ends thereof bent away from the intermediate portion in order to prevent tear- 50 ing or gouging of the surface of' bread.

It is obvious that since spring |0| tends to bias the bracket 95 and the arms 91 and 99 against the serrated edge |03 of slot |05 and since carv riage 4|` moves upwardly during the toasting 55 operation. the two arms will be moved in a generally vertical sinuous path upwardly and the tactile member |01 is so designed and positioned that it will engage one toasting surface of a; slice of bread being toasted. It will be noted that the o0 sinuous movement and in particular lthe movement in a horizontal direction is caused by engagement of arm 99 with the serrated edge |03. 'I'he design and construction of the arms 91 and 99 and the spring |0| is such that, as long as the 65 1 toasting surface -of a slice of bread is soft, the tactile member |01 will be forced into the slice of bread, but that it will not bev forced into the slice of bread when the surface hardness thereof has reached a certain value. inner end of arm 91 will tend to approach the inner end of arm 99 and this relative movement is made use' of to close a latch release circuit.

Arm 91 has mounted thereon a contact member -f When this occurs the |09 while arm 99 has mounted thereon a contact '(5 member which contact members are connected in an electric circuit at the same time as the heating elements are energized, which ele'ctric circuit includes a solenoid H3. A core H5 '-in the solenoid is pressed in one direction by a spring H1 (see Fig. 5) so that an extension ||9 on the core or armature H5 will be normally out of engagement with latch arm 19. The design, insulation and construction of arms 91 and 99 and contacts |09 and I|| are such that the electric circuit including the solenoid H3 will be normally deenergized but will be energized when contacts |09 and are in engagement. When engagement of contacts |09 and HI occurs by reason of a. lesser degree of movement of arm 91, than the movement of arm 99, because of the greater resistance to its bread-engaging movement when the toasting surface of the bread slice becomes harder, engagement of contacts |09 and IH will occur, thereby energizing solenoid H3, causing outward movement of core H5 and extension H9 and engagement of the latter with latch arm 19. This causes release of the member 11 from latch arm 19, opening of the switch and raising of the bread slice support into non-toasting position by the hereinbefore mentioned action of coil spring 1|.

Means for varying the degree of hardness at which engagement of contacts |09 and will occur, thereby terminating the toasting operation, includes an adjusting knob .|2| which may be rotatably mounted in the lower part of knob and. be secured'to a suitable shaft |23 extending through the slot in the front part of casing I5. A cam |25 is secured to the inner end of shaft |23 and engages the outer end of a spring `arm |21 insulatedly pivotally mounted on a part of bracket 95, as by a pivot pin |28, the inner end of arm |21 extending below arm 91 and engaging a depending portion |29'thereof so that more or less pressure maybe applied to the intermediate portion of arm 91 to tend to move it into engagement with the slice of bread |06. Thus if cam |25 is turned so that the inner end of arni |21 applies a pressure to arm 91 tending to bias it toward` a slice of bread the bread slice will be toasted to a greater degree before engagements of the two contacts |09 and HI will occur.

It is desirable that the front edge of a slice of bread'be in a definite position relative to the arms 91 and 99 and particularly with reference to the tactile member |01. In order to accomplish this the bread slice/i support 13 is provided at its front edge with a vertically extending stop I3 while the rear end of the bread slice suppdrt 13 is 'provided with a leaf spring |33 (see' Fig. 1) whereby a slice of bread |06 will be forced into close engagement with stop |3|. This fixes, position of the bread longitudinally of the support.

In order to fix the position of the inner edge of a slice of bread laterally thereof front intermediate wall 21 may be provided with an inwardly extending projection |35 (see Fig. 8) while the breadslice support 13 may be provided at one A side of its forward end with an upwardly extending leaf spring |31 effective to bias the bread slice |06"against flange |35, and to ensure that one toasting surface of successive bread slices shall be located in a predetermined position in the toaster irrespective of variations in the thickness of the different slices.

It is obvious, from the description thus far given of the structure associated with and operatingthe tactile member are moved downwardly when knob 45 is actuated |01 that these elements .toasted and effective to terminate a toasting opby an operator and that the bracket 95y and the spring arms 91 and 99 will bevmoved` upwardly gradually at the 'same time as Acarriage 4|` is moved upwardly and that the tactile member is,

moved into repetitive engagement with succes- 5 sively different portions of a toasting surface of a slice of bread which toasting surface is held in relatively fixed position in the toaster and particularly with relation to the tactile member.

It is obvious thatl when the surface hardness of 10 the toasting surface engaged by the tactile member has reached a certain value, arm 91A will be flexed slightly relatively to arm 99 causing engagement of contact membersy |09 and and energization of the release circuit including sole- 15 noid H3. When this solenoid isv energized extension H9 is moved away from the solenoid and into engagement with the upper end of latch arm 19 to effect release movement thereof of extension 11 from the detent end of latch arm 19 and 20 the resultant quick upward movement of bread slice support 13 in the toasting chamber and simultaneous opening of the energizing circuit of the heater and of solenoid H3.

The device embodying my invention permits 25 thereof. It is obvious that it will take a l nger 30v time to reach a desired degree of surface r'dness when starting with a cold toaster than is the case when a toaster has been used for Aevexigl immediately successive toasting operatic Since the hardness of a toasting surface of a 35q slice of bread is the criterion used to `determine the duration of a toasting ,operation no. com` pensating means whatever is required to correct for changes in the temperature of the toaster o itself.` l

The device embodying my invention is relatively simple and easily operable and while I have shown a particular form of prime mover. my invention isinot limited thereto since any other" form of prime mover effective to cause a return movementof the carriage and attendant repetitive contacting movements on a toasting surface may be used by me, such as a small electric motor energized simultaneously with the heating elements of the toaster.

It is also obvious that contact members |09 and Il may be normally in engagement and solenoid H3 normally energized with the armature Iland spring construction associated therewith changed soA that disengagement of the contact members and consequent deenergization of would effect release movement of member H9. In other words while I have shown a particular form of electro-magnetic release structure in 6 j'y the' solenoid which the coil is normally deenergized my inven- I tion is not limited thereto.

Various modifications may be made in the device embodying myv invention without departingJ 'from the spirit and scope thereof, and Iv desire therefore. that only such limitation shall be placed thereon as are imposed by the prior art or are set forth in the appended claims.

l I claim as my invention:

1. In an automatic toaster, the combination 0 'with a heating means for toasting a Aslice of bread and means for initiating `a toasting operation, of means for terminating a toast/ing operation operable in accordance with the surface hardness of a selected surface of a slice of bread being eration when the surface hardness of a selected V surfaceofasliceofbreadbeingtoastedhas increased to a c ertain value.

2. In -an automatic toaster, the combination with aheating means for toasting a slice of bread and means for initiating a toasting operation of means for terminating a toasting operation 'including a member reciprocably actuable into ment with a toasting surface of a slice of bread,

` power means connected to be energized six'nultaneously with the movement of the bread slice into toasting position for causing said movement of the tactile member and means controlled by said tactile member for causing movement of the toasted slice of bread out of said toasting position when the hardness of a toasting surface has increasedtca given value.k

4. hIn an automatictoaster, the combination with a heating means, a bread slice'support mov- 1 able rdativeiv to the heatingmeans into toasting and .nn-toasting-position and biased to non- 'toasting position and a detent vfor holding "the bread support in toasting position, of'a tactile element actuable to engage with and disengage from successively different portions of a toasting surface of a slice -of bread being toasted and means responsive to a predetermined movement of 'said tactile element to cause release of said detent when the hardness of a toasting surface of the bread being toastedhas increased to a predetermined value.

' v 5. In an automatic toaster, the combination with an electric heating means vfor toasting a slice of bread, a control switch for said heating means biased to open position and a detent for holding said switch in closed position, of an electromagnetic means for moving said detent to allow the control switch to open and means for controlling said electromagnetic means including means actuable in accordance with a predetermined increase in surface hardness of a toasting surface of a slice of bread being. toasted. v

6. In an automatic toaster, the combination with an electric heating means for toasting a slice of bread, a bread support movable into toastin'g and non-toasting positions relatively to said heating means and spring-biased to nontoasting position and a detent for holding said bread support in toasting position, of means for causing release of said detent after a time interval, said means including an electromagneticallyactuable detent release means, a control' for said electromagnetic means actuable in accordance with increase in the surface hardness of a toasting surface of a slice of bread being toasted and operable to cause release of said detent when the surface hardness of said toasting surface has increased to a certain value.

7. In an automatic toaster, the combination with an electric heating means for toasting a slice of bread, a control switch therefor, a bread support movable into toasting and non-toasting position relatively to said heating means, a single spring for biasing the switch to open position and the bread support to non-toasting position, means for simultaneously moving the switch to closed position and the bread support to toasting position and a detent for holding said switch in o closed position and said bread support in toasting position, of means for causing release of said detent after a toasting interval,`said means including a normally deenergized electromagnetically-actuable release mechanism'. an electric circuit therefor, a pair of cooperable contacts in said circuit normally in position to maintain said' circuit in deenergized condition, a tactile member supporting one of said contacts, periodically movable into engagement with a toasting surface of a slice of bread being toasted and operable to cause circuit energizing movement of said contacts when said toasting surface has been hardened to a certain degree.

8. In an automatic toaster, the combination with an electric heating means for toasting a slice of bread, a control switch therefor, a bread support movable into toasting and non-toasting. position relatively to said heating means, a single spring for biasing the switch to open position and the bread support to non-toastingposition, means for simultaneously moving the switch to closed position and the bread support to toasting position and a detent forholding said switch in closed position and said bread support in toasting position, of means for causing release of said detent after a toasting interval, said means including an electromagnetically-actuable detent release means, a normally open circuit therefor and circuit closing means including normally disengaged contacts connected in said circuit and a tactile member periodically movable into engagement with -a toasting surface of a slice of bread being toasted andadapted to cause engagement of said contacts when said toasting surface has been hardened to a certain degree.

9. In an automatic toaster, the combinationy with Aan electric heating means for toasting a slice of bread, a control switch therefor, a bread support movable into toasting and non-toasting position relatively to said heating means', a single spring for biasing the switch to open position and the bread support to non-toasting position, means for simultaneously moving the switch to closed position and the bread -support to toasting position and said bread support in toasting position, of means for causing release of said detent after a toasting interval, said means including a normally deenergized electromagnetically-actuable release mechanism, an electric circuit therefor, a pair of cooperable contacts in said circuit normally in position to maintain said circuit vin deenergized condition, a tactile member supporting one of said contacts, periodically movable into engagement with a toasting surface of a slice of bread being toasted and operable to cause circuit energizing movement of said contacts when said toasting surface has cluding a mechanical timer having means for winding it by said switch closing and bread support moving means and effective to then causey movement of said tactile member along and adv 11. A toaster as set forth in claim 9 and injacent to said toasting surface and into and out of engagement with said toasting surface.

12. A toaster as set forth i-n claim 9 and. in-

`cluding means on said bread support for holding a slice of bread supported thereby in a fixed position thereon.

13. A toaster as set forth in claim 4 in which the tactile element is movable along said toasting surface to successively engage different areas of said toasting surface.

14. In an automatic toaster, the combination with a pair of spaced electric heating elements, a casing therearound, a front intermediate wall cooperating with the heating elements to define a toasting chamber and with a part of said casing to define a mechanism chamber, a bread slice support movable between the heating elements into toasting and non-toasting positions, a control switch for the heating elements, a spring for biasing the switch to open position and the bread support to non-toasting position, means for simultaneously closing the switch and moving the bread support. to toasting position and a detent for holding the switch closed and the bread support in toasting position, of means for effecting a releasing movement of said detent When the surface hardness of a slice of bread being toasted has reached a certain value, said means including an arm supported at its outer end in said mechanism chamber and having its inner end extending into the toasting chamber through a slot in said front intermediate wall, a tactile member on the inner end of said arm adjacent a toasting surface of the bread, a second arm spaced from said rst arm and having its inner end adjacent the inner end of the first arm, contacts on said arms normally out of engagement with each other, an electromagnetic detent release means including an electric circuit and said contacts and means for causing reciprocating movement of said arms to vcause the tactile member to engage with and be disengaged from said toastingl surface and to cause circuitlclosing engagement of said contacts when the surface hardness of a slve of bread being toasted has reached a certain value, to cause release of said detent.

15. A toaster as set forth in claim. 7 in which said bread slice support includes means for denitely fixing the position of a toasting surface o f a slice of bread in the support relatively to said tactile member.

16. A toaster as set forth in claim 7 in which the means causing movement of said tactile member includes la mechanical timer for causing said tactile member to move in a direction substantially parallel `With a toasting surface of a slice of bread and a serrated edge wall of said slot in the front intermediate wall engaged by one of said arms.

17. A toaster as set forth in claim 14 and including a knob on the outside of said casing connected to vary the position of one of said arms relatively to the other arm to vary the degree of surface hardness at Which said detent is released.

18. The method of determining the duration of a toasting operation on a slice of bread which comprises intermittent repetitive testing of the hardness of successively different portions of a toasting surface of a slice of bread being toasted by heat from a heating means during said op eration and terminating said toasting operation when the surface hardness of the bread has increased to a given value.

19. The method of determining the duration of l a toasting operation on a slice or" bread whichbeing toasted by heat from a heat source and ei` i" fecting a separating movement between the heat source and the slice of bread when the surface hardness of the bread has increased to a giz'en value.

WIILIAM L. LODGE. 

